How to generate multiple random combinations of word pairs with specific restrictions on avoiding repetition?

1. I want to randomly combine word pairs such that I can generate an instruction - e.g., "Spin yellow rubber".

Actions={'spin',
       'pick up',
       'push',
       'touch',
       'shake',};
Objects={'yellow rubber',
       'white rubber',
       'pink ruler',
       'blue ruler',
       'orange folder',
       'green folder',
       'purple bag',
       'brown bag',
       'gold box',
       'black box',
       'red pencil',
       'grey pencil'};

2. I'd like to expand this to generate a sequence of 4 instructions - e.g., "spin yellow rubber, pick up pink ruler, push orange folder, touch gold box'. I want to generate 192 sets of four-sequence instructions [192 x 4].

3. I don't want repetitions of the action AND the object within the sequence of 4 instructions. In my 192 x 4 instructions, I do not want the instruction (e.g., spin yellow rubber) to appear in two consecutive rows.

Answer 1

[Mathieu NOE]

@ Abi

this is the last iteration of the code

Actions={'spin',
       'pick up',
       'push',
       'touch',
       'shake',};
Objects={'yellow rubber',
       'white rubber',
       'pink ruler',
       'blue ruler',
       'orange folder',
       'green folder',
       'purple bag',
       'brown bag',
       'gold box',
       'black box',
       'red pencil',
       'grey pencil'};
   
   n = numel(Actions);
   m = numel(Objects);
   
   
% create a vector of random integer values 
% rows 1 / 3 / 5 / 7 : range : 1 to n
% rows 2 / 4 / 6 / 8 : range : 1 to m
candidates = 2e4; % nb of initial candidates
v1357 = randi([1 n],candidates,4);
v2468 = randi([1 m],candidates,4);

A = [v1357(:,1) v2468(:,1) v1357(:,2) v2468(:,2) v1357(:,3) v2468(:,3) v1357(:,4) v2468(:,4)];
k = 0;
q = 0;

C = 0;
B_old = zeros(1,8);

for ci = 1 : candidates
    B = A(ci,:);
    
    cond1 = (B(1) == B_old(1)) & (B(2) == B_old(2)); % test if first pair is identical to previous 1st pair 
    cond2 = (B(3) == B_old(3)) & (B(4) == B_old(4)); % idem for 2nd pair
    cond3 = (B(5) == B_old(5)) & (B(6) == B_old(6)); % idem for 3rd pair
    cond4 = (B(7) == B_old(7)) & (B(8) == B_old(8)); % idem for 4tg pair
    
    test_previous = any([cond1 cond2 cond3 cond4]);
    
    if (length(unique(B)) == 8) && (test_previous == 0) % keep only if all 8 elements are different and no duplicate pairs with previous iteration
        k = k+1;
        C(k,1:8) = B;
        B_old = B;
    end
      
end
    
% crop to first 192 rows
C = C(1:192,:);

for ck = 1:192
    out = [Actions(C(ck,1)) {' '} Objects(C(ck,2)) {' '} Actions(C(ck,3)) {' '} Objects(C(ck,4)),...
        {' '} Actions(C(ck,5)) {' '} Objects(C(ck,6)) {' '} Actions(C(ck,7)) {' '} Objects(C(ck,8))];
    myWords{ck} = [out{:}];
end

FinalWords = myWords';

[Abi Fiske]

@Mathieu NOE This is great, thank-you so much! You are very kind to help me with this script. All the best.

[Mathieu NOE]

Glad it helped !

Answer 2

[Mathieu NOE]

Did I won the prize ?

Actions={'spin',
       'pick up',
       'push',
       'touch',
       'shake',};
Objects={'yellow rubber',
       'white rubber',
       'pink ruler',
       'blue ruler',
       'orange folder',
       'green folder',
       'purple bag',
       'brown bag',
       'gold box',
       'black box',
       'red pencil',
       'grey pencil'};
   
   n = numel(Actions);
   m = numel(Objects);
   
   
% create a vector of random integer values 
% 1st and 3rd row range : 1 to n
% 2nd and 4th row range : 1 to m
l = 500;
v1 = randi([1 n],l,1);
v3 = randi([1 n],l,1);
v2 = randi([1 m],l,1);
v4 = randi([1 m],l,1);

A = [v1 v2 v3 v4];
k = 0;
C = 0;
for ci = 1 : l
    B = A(ci,:);
    if length(unique(B)) == 4 % keep only if all 4 elements are different 
        k = k+1;
        C(k,1:4) = B;
    end
end
    
% crop to first 192 rows
C = C(1:192,:);

for ck = 1:192
    out = [Actions(C(ck,1)) {' '} Objects(C(ck,2)) {' '} Actions(C(ck,3)) {' '} Objects(C(ck,4))];
    myWords{ck} = [out{:}];
end

FinalWords = myWords';

[Abi Fiske]

This is absolutely amazing - thank-you so much! You win first prize!

Would you be able to help with a slight tweak to the code? At the moment, the code generates 2 instructions per cell "e.g., spin orange folder push grey pencil". Would it be possible for there to be 4 instructions per cell, and that there is no repetition of action or object within this cell?

I am happy to include an acknowledgement of your name as the script author in any future publications that come from this work.

[Mathieu NOE]

hello Abi

that shouldn't be too complicated....

having my name in your publication is maybe a bit too much for a simple piece of matlab code - or ?

[Abi Fiske]

Hi,

Great, thanks! Well it is a courtesy to acknowledge you as the script writer in the acknowledgements section. If you are willing to help me without acknowledgement, then that's fine too. I'm very grateful for your help with this simple code that will save us lots of time!

[Mathieu NOE]

job done !

Actions={'spin',
       'pick up',
       'push',
       'touch',
       'shake',};
Objects={'yellow rubber',
       'white rubber',
       'pink ruler',
       'blue ruler',
       'orange folder',
       'green folder',
       'purple bag',
       'brown bag',
       'gold box',
       'black box',
       'red pencil',
       'grey pencil'};
   
   n = numel(Actions);
   m = numel(Objects);
   
   
% create a vector of random integer values 
% rows 1 / 3 / 5 / 7 : range : 1 to n
% rows 2 / 4 / 6 / 8 : range : 1 to m
candidates = 2e4; % nb of initial candidates
v1357 = randi([1 n],candidates,4);
v2468 = randi([1 m],candidates,4);

A = [v1357(:,1) v2468(:,1) v1357(:,2) v2468(:,2) v1357(:,3) v2468(:,3) v1357(:,4) v2468(:,4)];
k = 0;
C = 0;
for ci = 1 : candidates
    B = A(ci,:);
    if length(unique(B)) == 8 % keep only if all 8 elements are different 
        k = k+1;
        C(k,1:8) = B;
    end
end
    
% crop to first 192 rows
C = C(1:192,:);

for ck = 1:192
    out = [Actions(C(ck,1)) {' '} Objects(C(ck,2)) {' '} Actions(C(ck,3)) {' '} Objects(C(ck,4)),...
        {' '} Actions(C(ck,5)) {' '} Objects(C(ck,6)) {' '} Actions(C(ck,7)) {' '} Objects(C(ck,8))];
    myWords{ck} = [out{:}];
end

FinalWords = myWords';

[Abi Fiske]

This is brilliant and works well- thank-you so much for your help, Mathieu! I am extremely grateful. If you don't mind, I have one (hopefully last) challenge for you that may or may not be possible...

It would be great to make sure that the same instruction (action and object pairing) don't appear in the same position in the previous or next instruction. So it would be best to avoid the following scenario:

touch the blue ruler, spin the red pencil, spin the gold box, shake the green folder

spin the pink rubber, touch the orange folder, pick up the grey pencil, shake the green folder

Is this possible?

[Walter Roberson]

Wouldn't it be better to use randperm() to avoid any possibility of duplication?

[Mathieu NOE]

Sure - I was thinking going this way for a better coding

[Mathieu NOE]

@ Walter

I am not aware that randperm can generate a 2D array of random values with the guarantee to not have repeated values along both the row / column dimensions ?

it works only for 1D array as far as I know

tx for your help

[Mathieu NOE]

also randperm does not allow me to generate more numbers than the max value of the range

so if my range is 1:4 , I get only 4 values which is not my intention. And looping is not an option as I loose the uniqueness of the random values.